MY D-Link-Xtreme N™ Dual Band USB Adapter (DWA-160) DOES NOT WORK PROPERLY

Two days back I had purchased D-Link-Xtreme N™ Dual Band USB Adapter (DWA-160). This purchase was made with a big expectation i.e the manufacturer(Dlink) says its feature is "DELIVERS FASTER SPEEDS AND FURTHER RANGE THAN 802.11g SO YOU GET STRONG SIGNALS FROM VIRTUALLY EVERY CORNER OF YOUR HOME" but unfortunately it happened to give the same result of my Acer Notebook's built in Adapter (Atheros AR5007EG Wireless Network Adapter), it neither gives further range nor gives strong signals. I use D-Link-DSL-2740B RangeBooster N™ ADSL/ADSL2/2+ Modem Router as WLAN Access Point. i use windows XP SP3.

briefing my troubleshooting(inspite of these i couldn't get the result):
1> i tried matching the channel number by bringing change in my AP
2> called up the DLink support
3>disabled my inbuilt adapter(wireless)
4>made sure that no barriers in between

I believe there must be some configuration still to be completed with respect to my USB Adapter and my WLAN Access Point in order to enjoy the complete efficiency D-Link promises. I expect the solutions at the earliest possible.